Vehicle dynamics control system

ABSTRACT

A control system for a vehicle is provided that uses the frame of the vehicle as a sensory input to control various components of the vehicle. The control system includes one or more sensor assemblies that are mounted to the vehicle frame with each sensor assembly including one or more strain sensors generating signals indicative of the strain on the frame. The system further includes an electronic control unit that controls components such as the throttle valve, brakes, and warning indicators responsive to the signals generated by the strain sensors.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a control system for a vehicle and, inparticular, to a control system that uses the vehicle frame as a sensoryinput in controlling various components of the vehicle.

2. Discussion of Related Art

As electronic control of vehicles continues to evolve, numerouselectronic control systems have been and are being developed to controlconventional mechanical components of the vehicle. Electronic throttlecontrol, electronic fuel injection, tire pressure management, and ABSbrakes are just a few of the many examples of the use of electroniccontrol systems in vehicles. Many conventional control systems, however,are restricted by the response times generated from sensor inputs.Further, conventional control systems often require the use ofrelatively expensive sensors.

The inventors herein have recognized a need for a vehicle control systemthat will minimize and/or eliminate one or more of the above-identifieddeficiencies.

SUMMARY OF THE INVENTION

The present invention provides a control system for a vehicle.

A control system in accordance with the present invention includes aplurality of sensor assemblies mounted on a frame of the vehicle. Thesensors assemblies may be mounted in various locations on the frame ofthe vehicle and, in one embodiment, the sensor assemblies are mounted onthe frame proximate each wheel of the vehicle and on front and rearcross members of the vehicle frame. Each of the sensor assembliesincludes at least one strain sensor. The strain sensor generates astrain indicative signal indicative of strain on the vehicle frame. Thecontrol system further includes an electronic control unit (ECU). TheECU controls operation of a component of the vehicle responsive to thestrain indicative signals generated by the strain sensors of the sensorassemblies. The vehicle component may, for example, comprise a throttlecontrol valve or shock absorber.

A control system in accordance with the present invention represents asignificant improvement as compared to conventional control systems.First, the use of the frame as a sensor substantially increases controlresponse times of the control system. Second, the use of strain sensorsprovides a relatively inexpensive sensor arrangement. Third, theintegration of the strain sensors and ECU into the vehicle structurewill reduce assembly and inventory handling costs.

These and other advantages of this invention will become apparent to oneskilled in the art from the following detailed description and theaccompanying drawings illustrating features of this invention by way ofexample.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a portion of a vehicle incorporating acontrol system in accordance with the present invention.

FIGS. 2-4 are block diagrams illustrating power distribution and controlin a control system in accordance with the present invention.

FIG. 5 is a block diagrams illustrating the interconnection of sensorassemblies and the electronic control unit of the inventive controlsystem.

FIG. 6 is a block diagram illustrating a sensor assembly of theinventive control system.

FIG. 7 is a block diagram illustrating a control system in accordancewith the present invention.

DETAILED DESCRIPTION OF ONE OR MORE EMBODIMENTS OF THE INVENTION

Referring now to the drawings wherein like reference numerals are usedto identify identical components in the various views, FIG. 1illustrates a portion of a vehicle 10 incorporating one embodiment of acontrol system 12 in accordance with the present invention. Vehicle 10may comprise any of a wide variety of conventional vehicles including,but not limited to automobiles, light and heavy trucks, and off-roadvehicles. Among other components, vehicle 10 may include a frame 14,axles 16, 18, and wheels 20,22,24,26.

Frame 14 is provided to support a conventional vehicle body on axles 16,18. Frame 14 is conventional in the art and may be made fromconventional metals and metal alloys. In the illustrated embodiment,frame 14 includes a pair of spaced longitudinal rails 28, 30 extendingin the direction of vehicle travel and in the longitudinal direction ofvehicle 10 and several cross-members 32, 34, 36, 38. It should beunderstood that the size, shape, and configuration of frame 14 will varyin accordance with various vehicle design parameters and the illustratedframe embodiment is not intended to limit the scope of the disclosedinvention.

Rails 28, 30 are provided to secure and align the body (not shown) ofvehicle 10 on frame 14 and are conventional in the art. The size, shape,and configuration of rails 28, 30 will vary depending upon designrequirements associated with vehicle 10.

Cross-members 32, 34, 36, 38 are provided to connect rails 28, 30 and tosupport other components of vehicle 10 (e.g., the engine). Members 32,34, 36, 38 are conventional in the art and it should again be understoodthat the number of cross-members as well as the size, shape, andconfiguration of cross-members, may vary depending upon designrequirements associated with vehicle 10.

Axles 16, 18 are provided to rotatably support wheels 20, 22 and 24, 26,respectively, and to support other components of vehicle 10 such assuspension and brake system components. Axles 16, 18 are conventional inthe art and may be forged or otherwise formed from a variety ofconventional metals and metal alloys. In the illustrated embodiment,axle 16 comprises a steer axle, while axle 18 comprises a drive axle.Although the illustrated vehicle includes only two axles, it should beunderstood that the present invention may find use in vehicles havingany number and type of axle.

Wheels 20, 22, 24, 26 are provided to mount the tires and areconventional in the art. Wheels 20, 22, 24, 26 are rotatably supportedon axles 16, 18 in a conventional manner. For example, wheels 20, 22 maybe supported on a spindle extending from a steering knuckle (not shown)that is coupled to axle 16 through a conventional kingpin connection(not shown). Wheels 24, 26 may be supported on axle half shafts (notshown) driven by a differential (not shown) and extending from thehousing of drive axle 18. Wheels 22, 24, 26, 28 are also suspended fromframe 14 by conventional suspension systems having components such ascontrol arms, springs, and shock absorbers.

Control system 12 is provided to control one or more components ofvehicle 10. The components controlled may include, for example, thethrottle valve (not shown), shock absorbers (not shown) or othersuspension components, a torsion bar coupled to frame 14, and brakesystems (not shown). Control system 12 may also control components suchas indicators that generate signals to the vehicle operator indicativeof some characteristic of vehicle 10 such as tire pressure, balance, andshape, brake wear, vehicle load, and tongue weight. These indicators maybe visual, audio, or a combination of the two, or may be designed totrigger other human senses (e.g., tactile senses through vibration).Control system 12 may include a power control assembly 40, communicationinterfaces 42, sensor assemblies 44 _(FL), 44 _(FT), 44 _(FR), 44 _(RL),44 _(RT), and 44 _(RR) (collectively and generically identified by thenumeral 44 hereinafter) and an electronic control unit (ECU) 46.

Power control assembly 40 is provided to distribute power to sensorassemblies 44. Referring to FIG. 2, assembly 40 may include a powersupply 48 (such as a 12 volt or 42 volt battery), a plurality of powerdistribution modules 50 _(FL), 50 _(FR), 50 _(RI), and 50 _(RR), and awiring harness 52 configured to distribute power from the power supply48 to the power distribution modules 50 (collectively and genericallyidentified by the numeral 44 hereinafter). Referring to FIGS. 3-4, eachpower distribution module 50 may include a conventional switching device54 such as a smart field effect transistor that controls the flow ofpower from harness 52 to one or more sensor assemblies 44 responsive toa control signal from ECU 46. A current estimate of the power requiredfor each power distribution module 50 is 1200 watts, but as much as 4000watts may be required. Each sensor assembly 44 is expected to requirebetween three (3) and eight (8) volts for proper operation.

Communication interface 42 is provided to interface ECU 46 with otherelectronic control units in vehicle 10. For example, ECU 46 mayinterface with the engine electronic control unit, the electroniccontrol unit for the braking system, and the electronic control unitused to send and receive vehicle operator information. Interface 42 isconventional in the art and may include one or more wiring harnessesincorporating twisted pair cables as well as connectors at varioustermination points on the harness.

Sensor assemblies 44 are provided to transmit signals to ECU 46indicative of the strain on frame 14 of vehicle 10. Referring to FIG. 1,assemblies 44 may be disposed in a variety of locations relative toframe 14. In one embodiment of the invention, sensor assemblies 44_(FL), 44 _(RL), and 44 _(FR), 44 _(RR) are disposed on rails 28 and 30,respectively, of frame 14, proximate each wheel 20, 22, 24, 26 ofvehicle 10, and sensor assemblies 44 _(FT), 44 _(RT), are disposed oncross-members 32, 38 of frame 14. Referring to FIG. 5, a wiring harness56 may be used to route signals between sensor assemblies 44 and ECU 46.The harness 56 may incorporate twisted pair cables. Referring now toFIG. 6, each sensor assembly 44 may include a sensor package 58including a plurality of strain sensors 60 and an integrated electronicspackage 62, and means, such as mounting plate 64, for mounting assembly44 to frame 14.

Strain sensors 60 are provided to indicate strain on areas of frame 14.Sensors 60 are conventional in the art may be formed from silicone usingmicro machining technology. In the illustrated embodiment, each sensorassembly 44 includes four strain sensors 60, although it will beunderstood that the number of strain sensors 60 may vary. The strainsensors 60 in each assembly 44 are redundant and bridged to providecommon mode noise rejection. Sensors 60 generate strain indicativesignals indicative of the strain on frame 14.

Package 62 is provided to condition and potentially process the strainindicative signals generated by sensors 60. Package 62 may includeconventional circuitry for impedance matching, amplification,conditioning, summing, and analog to digital conversion. Package 62 mayalso include a digital signal processor for preprocessing signals priorto delivery to ECU 46.

Mounting plate 64 is provided to mount sensor assembly 44 to frame 14.Plate 64 may comprise a metal substrate to which sensor package 58 isbonded. Plate 64 may be coupled to frame 14 using conventional fasteners(not shown) or by welding.

Referring now to FIG. 7, ECU 46 is provided to generate control signalsused to control one or more components of vehicle 10 responsive to thestrain indicative signals generated by sensor assemblies 44. ECU 46 maycomprise a programmable microprocessor or microcontroller or maycomprise an application specific integrated circuit (ASIC). ECU 46 mayinclude conventional components such as a central processing unit (CPU),an input/output (I/O) interface and memory. ECU 46 may be configured toprocess input signals and generate output signals used to controlcomponents of vehicle 10 by programming instructions or code (i.e.software). These instructions may be encoded on a computer storagemedium such as a conventional diskette or CD-ROM and may be copied intothe memory of ECU using conventional computing devices and methods.

ECU 46 receives inputs from each of sensor assemblies 44. In addition,ECU 46 may receive input signals from other conventional vehicle sensorsand use these input signals together with the strain indicative signalsto control components of vehicle 10. For example, ECU 10 may receive asteering angle indicative signal from a steering angle sensor 66, aspeed indicative signal from a vehicle speed sensor 68, an accelerationindicative signal from an accelerometer 70, a brake signal from a wheelend ABS sensor 72, and a throttle position indicative signal from athrottle position sensor 74. Those of skill in the art will understandthat signals generated by other conventional vehicle sensors may beinput to ECU 46 as well for use in controlling components of vehicle 10.

ECU 46 generates one or more control signals used to control variouscomponents of vehicle 10. As set forth hereinabove, the componentscontrolled by ECU 46 may include a throttle valve 76, ABS brakingsystems 78, shock absorbers 80 or other suspension components, a torsionbar 82, or various indicators 84 for the vehicle operator. Throughcontrol of such components, system 12 is able to exercise control overvehicle stability, rollover protection systems, ride height, and activesuspension damping. The programming instructions or code for ECU 46 maybe written in a modular format to enable potential customers to purchasecontrols for individual vehicle components (e.g., a shock absorber) orvehicle characteristics (e.g., rollover protection). The modular formatis advantageous in allowing a manufacturer to offer for sale andmanufacture vehicles having only those control features the customerwants.

A control system in accordance with the present invention represents asignificant improvement as compared to conventional vehicle controlsystems. In particular, the inventive control system increases theresponse time for controlling various vehicle components from sensorinputs by integrating strain sensors into the vehicle frame and usingthe vehicle frame itself as a sensor. The inventive system also isrelatively inexpensive. In particular, the use of strain sensorsprovides a less costly alternative to sensors more commonly used invehicle control systems today. Further, the integration of the sensorsinto the vehicle frame will reduce assembly and inventory handlingcosts.

While the invention has been shown and described with reference to oneor more particular embodiments thereof, it will be understood by thoseof skill in the art that various changes and modifications can be madewithout departing from the spirit and scope of the invention.

1. A control system for a vehicle, comprising: a first sensor assemblymounted on a frame of said vehicle, said first sensor assembly includinga first strain sensor generating a strain indicative signal indicativeof strain on said frame; and, an electronic control unit for controllingan operation of a component of said vehicle responsive to said strainindicative signal.
 2. The control system of claim 1, further comprisinga throttle position sensor that generates a throttle position indicativesignal, said electronic control unit controlling operation of saidcomponent responsive to said strain indicative signals and said throttleposition indicative signal.
 3. The control system of claim 1, furthercomprising a steering angle sensor that generates a steering angleindicative signal, said electronic control unit controlling operation ofsaid component responsive to said strain indicative signals and saidsteering angle indicative signal.
 4. The control system of claim 1,further comprising an accelerometer that generates an accelerationindicative signal, said electronic control unit controlling operation ofsaid component responsive to said strain indicative signals and saidacceleration indicative signal.
 5. The control system of claim 1,further comprising a vehicle speed sensor that generates a speedindicative signal, said electronic control unit controlling operation ofsaid component responsive to said strain indicative signal and saidspeed indicative signal.
 6. The control system of claim 1, furthercomprising a wheel end ABS sensor that generates a brake indicativesignal, said electronic control unit controlling operation of saidcomponent responsive to said strain indicative signal and said brakeindicative signal.
 7. The control system of claim 1 wherein saidcomponent comprises a shock absorber.
 8. The control system of claim 1wherein said component comprises a torsion rod coupled to said frame. 9.The control system of claim 1 wherein said component comprises a wheelbrake of said vehicle.
 10. The control system of claim 1 wherein saidcomponent comprises a throttle valve.
 11. The control system of claim 1wherein said component comprises an indicator that provides anindication of a characteristic of said vehicle to an operator of saidvehicle.
 12. The control system of claim 16, wherein each of said firstand second sensor assemblies is disposed proximate a different wheel ofsaid vehicle on one of first and second longitudinal rails of saidframe.
 13. The control system of claim 1 wherein said first sensorassembly is disposed on a cross member of said frame between first andsecond longitudinal rails of said frame.
 14. The control system of claim1 wherein said first sensor assembly includes a second strain sensorgenerating a strain indicative signal indicative of strain on saidframe.
 15. The control system of claim 1 wherein said first sensorassembly includes a metal substrate coupled to said frame.
 16. Thecontrol system of claim 1, further comprising a second sensor assemblymounted on said frame of said vehicle, said second sensor assemblyincluding a first strain sensor generating a strain indicative signalindicative of strain on said frame wherein said electronic control unitcontrols said operation of said component of said vehicle responsive tosaid strain indicative signals of said first and second sensorassemblies.